Method of making composite products incorporating textile fabrics



Ap 3, 1963 M. ARNETT METHOD OF MAKING COMPOSITE PRODUCTS INCORPORATINGTEXTILE FABRICS Filed May 19, 1959 United States Patent 3,086,274 METHODOF MAKING COMPOSITE PRODUCTS INCORPORATING TEXTILE FABRICS MeyrickArnett, Leyland, England, assignor to BTR Industries Limited, London,England, a British company Filed May 19, 1959, Ser. No. 814,157 Claimspriority, application Great Britain May 19, 1958 7 Claims. (Cl. 28-74)The invention relates to a method of producing woven textile fabrics forincorporation in composite products of the type set forth, to a methodof manufacture of such products. The type of composite products withwhich the invention is concerned comprise woven textile fabrics embeddedin, or bonded to, elastomeric materials such as rubber, syntheticrubber, or plasticised polyvinyl chloride or similar plastic material.The products may be utilised in, or as, conveyor belting, hose, and forother purposes where a flexible product combining strength and a wearresisting surface are required.

The invention provides the method of making a composite product of thetype set forth which comprises bonding to, or embedding in, anelastomeric material, a fabric having some warp and/ or some weftthreads with a greater crimp than other warp and/ or weft threadsrespectively and which has been produced by Weaving the fabric with somewarp threads and/or some weft threads having different shrinkage orstress recovery characteristics from other warp and/ or weft threadsrespectively, and effecting during or after weaving such differentialshrinkage or stress recovery between the warp and/or weft threadswhereby some of the threads have greater crimp than others.

The invention further provides the method of making a composite productof the type set forth which comprises weaving a textile fabric with somewarp threads and/or some weft threads having different shrinkage orstress recovery characteristics from other warp and/ or weft threadsrespectively, effecting during or after weaving such differentialshrinkage or stress recovery between the warp and/or weft threadswhereby some of the threads have greater crimp than others and bondingthe resultant fabric to, or embedding it in, an elastomeric material.

Preferably in carrying out either of the above forms of the method, thethreads having the lesser crimp are made from continuous filament yarns(e.g. nylon or rayon) and the threads having the greater crimp are madefrom staple yarn (e.g. cotton or staple nylon).

The invention includes products of the type set forth when made byeither form of the method.

More specifically, the fabric used in carrying out the invention hasWarp threads with different degrees of crimp or waviness whereby thosewith lesser crimp are adapted to take a tensile stress applied to thefabric and those with greater crimp are caused, by the weft threads, toprovide cover portions (erg. ribs) raised from the general surface ofthe fabric. The crimp in the warp threads, especially when they are ofstaple fibre construction provides effective keying means for bonding tothe fabric rubber, polyvinyl chloride or other material which is bondedthereto, or in which the fabric is embedded. At the same time thisconstruction of fabric provides protection for the stress taking threadsagainst impact damage and the fabric is also found to have good tearresisting properties.

Preferably the differential recovery or shrinkage which textile threadsof different compositions exhibit after being tensioned and stretched ina loom during weaving is employed to provide in the product threads ofdifferential lengths and hence different degrees of crimp.

In the accompanying drawings:

FIG. 1 is an enlarged plan view of the presently preice ferred fabricembodying the invention as it appears under weaving tension;

FIG. 2. is a transverse sectional view through the fabric of FIG. 1parallel with the weft of the fabric;

FIG. 3 is a sectional view parallel with the warp threads of the fabricshown in FIG. 1;

FIG. 4 is a sectional view taken similar to FIG. 3 but showing thecondition of the fabric after the warp threads have been permitted tocontract and the fabric has thereafter been embedded in an elastomericmaterial;

FIG. 5 is a plan view similar to FIG. 1 but showing the inventionembodied in a fabric of different weave;

FIG. '6 is a transverse sectional view through the fabric of FIG. 5parallel with the weft of the fabric;

FIG. 7 is a sectional view of the fabric in FIG. 5 parallel with thewarp threads of the fabric; and

FIG. 8 is a sectional view taken similarly to FIG. 7 but showing thecondition of the fabric after the warp threads have been permitted tocontract and the fabric has thereafter been embedded in an elastomericmaterial.

As already stated, in one form of the fabric employed in the invention,some of the warp threads are of continuous filaments (e.g. nylon orrayon) and other warp threads are formed of staple yarn (e.g. nylon orcotton), the continuous filament threads having the greater recovery orshrinkage and hence, in the product, constituting the load carryingthreads.

It is preferred that the load/ elongation characteristics of thedifferent warp threads or yarns are, in relation to their respectivecrimp in the fabric, such that when the fabric is subjected to maximumtensile working load (eg, about 30% of the ultimate strength) then thethreads or yarns will also be subjected to about their maximum workingloads.

Various methods of treatment may be employed to bring about thedifferential degrees of crimp in the warp or other threads. For example,when the warp threads are of suitably different materials as outlinedabove, they may all be subjected to the same degree of tension duringweaving with the result that those threads with the lesser recoveryafter release of the tension (e.g. threads of staple yarn) will havegreater crimp than those with greater recovery. Differential recovery ofthreads subjected to the same tension may also be obtained by the use ofthreads of different twist. Alternatively greater tension may be appliedin the loom to those threads which are to have lesser crimp in order toeffect greater elongation thereof and greater recovery on release of thetension.

In another alternative, the result is obtained by heat or moisturetreatment during or after weaving in order to obtain a differentialshrinkage of the threads. For instance in the case of fabric having warpthreads composed of fibres of coarse staple cotton and continuousfilament nylon respectively, the woven cloth may be subjected tosteaming to causethe nylon portion of the cloth to shrink.

, This operation may be followed by length-wise and crosswise stress tocontrol the degree of shrinkage and the threads subjected to cooling byair or water. Another method of obtaining differential crimp is toinsert a high twist into a thin yarn, ultimately to have the lessercrimp, set the twist by treatment with a water saturated size, weave thefabric and then wash out the size. This will cause the yarn of lessertwist to have greater crimp and rise to the surface.

When the treatment of the threads is carried out after weaving either asan auxiliary to the treatment during weaving or as the main treatment,it may form part of a press vulcanising or like operation primarilyconnected with the application of the elastomeric material and consistof an addition thereto or a modification thereof. It may employ heat,pressure or moisture or combinations thereof.

As a further alternative, the differentiation in recovery or shrinkagemay be obtained wholly or mainly by the use of threads of the sameconstruction but of different diameters. For example the threads withlesser recovery characteristics (i.e. those which are to have thegreater crimp) may have a diameter up to about four times that of thethreads of greater recovery characteristics.

It is not essential that the two kinds of threads are equal in number.

The following is an example of a woven fabric according to the inventionand suitable for use in a conveyor belt:

MATERIAL Warp (Stress) Type Nylon type 600. Denier 840. FilamentContinuous.

Warp (Cover) Type American cotton. Staple 1" ave. Preparation Carded.

Weft

Type Staple nylon (Indus. 4.0 g./d.). Staple 2 /2" ave. PreparationCotton system.

CONSTRUCTION Standard Wt./sq. yd. (02s.) 18.70. Ends/inch (cover) 20.Ends/inch (stress) 20. Picks/inch 14. Warp yarn constr. (cover) 3/ 7s.Warp yarn constr. (stress) 3/ 840D. Weft yarn constr 4/ 7s. Cover warpsingles t.p.i 7.28 (2). Cover warp ply t.p.i 5.5 (8). Stress warpsingles t.p.i 0.75 (2). Stress warp ply t.p.i 1.5 (S). Weft singlest.p.i 7.28 (2). Weft ply t.p.i 4.5 (S). Warp tensile 750 lbs. Percentelong. at break 27%. Weft tensile 350 lbs. Percent elong. at break 19%.Crimp cover warp 16%. Crimp stress warp 14%. Crimp weft 4%.

Warp arrangement: One cover end, one stress end working 2 as l.

Weave: Plain order.

FIGS. 1-4 illustrate a fabric having the above enumeratedcharacteristics. As indicated in FIGS. 1 and 2, the warp threads 19 and11 are under equal tension during the weaving operation with the warpthreads 10 formed of continuous filament nylon yarn and the warp threads11 formed of staple cotton yarn. The warp threads 10 and 11 are woven inpairs with the continuous filament warp threads having a lesser twistand a lesser cross sectional area than the warp threads 11. Thisdifference in size and construction of the warp threads results in asmall difierence in the crimp or undulations thereof about the weftthreads 12 even under the weaving tension, see FIG. 3. However, thedifference in crimp or undulations is accentuated, as indicated in FIG.4, when the weaving tension is released and the fabric is condensed inthe direction of its length. {This figure also shows the manner in whichthe threads 12 interlock with elastomeric material M when the fabric iscovered by or embedded in such material.

Modifications may be made in the above example. For instance the coverends may be worked separately from the stress ends.

This embodiment is illustrated in FIGS. 5-8. As shown in FIGS. 5 and 6,the continuous filament warp threads 13 and the staple yarn threads 14,which may be similar in construction, respectively, to the threads 10and 11 of the embodiment illustrated in FIGS. l4, alternate across theweft of the fabric but do not pass in pairs above and beneath the weftthreads 15. Instead, the adjacent warp threads pass on opposite sides ofeach weft thread 15. The crimp or undulations of the warp threads 13 and14 under the weaving tension is indicated in FlG. 7 while the increasedcrimp and the resulting accentuation of the extent of the projection ofthe bends of the warp threads 14- beyond the faces of the fabric, as theresult of contraction of the warp threads 13 when the weaving tension isreleased, is indicated in FIG. 8. This latter figure also illustratesthe locking of the threads 14- with elastomeric material M when thefabric is covered by or embedded in such material.

It will be evident that similar results are achieved by weaves otherthan the two specifically illustrated and that accentuation of the crimpof certain of the threads of the fabric relative to the other threadsthereof can be effected by one or more of the expedients mentionedheretofore as Well as by the specifically discussed and illustrateddifference in the warp tension during and after weaving.

When the fabric is to be incorporated in a belt, it is important thatthe material employed for the threads should be able to withstand thetemperatures and other conditions used in the coating or impregnation ofthe fabric.

The fabric of the present invention may be used as the fabric in theconstruction described and illustrated in British specification No.811,108.

I claim:

1. The method of making a fabric reinforced elastomeric material adaptedfor use in articles subject to tension comprising providing a fabricincluding interwoven threads extending generally in directionslengthwise and crosswise of the fabric, respectively, with alternatethreads in the lengthwise direction of the fabric contractible bydifferent amounts and with any single thread of said alternate threadsformed of a single textile substance, subjecting all of the threads inthe lengthwise direction to uniform tension during weaving, subjectingthe fabric to a thread-contracting condition after weaving whereby thoseof said alternate threads which contract the lesser amount acquiregreater crimp than those of greater contractibility thereby formingspaced projections on either face of the fabric while the said alternatethreads which contract the greater amount comprise tensionresistantelements in the fabric, and applying elastorneric material to the fabricwith the said material penetrating between the spaces provided by thesaid projections.

2. The method of making a fabric for use in reinforced elastomericarticles subject to tension comprising interweaving threads extendinggenerally lengthwise and crosswise, respectively, of the completedfabric with alternate ones of the threads extending in the lengthwisedirection contractible a greater amount than the threads with which theyalternate and with any single thread of said alternate threads formed ofa single textile substance, subjecting all of the threads in thelengthwise direction to uniform tension during weaving, and subjectingthe fabric to a thread-contracting condition after weaving whereby thoseof said alternate threads which contract the lesser amount acquiregreater crimp than those of greater contractibility thereby formingspaced projections on either face of the fabric facilitating adhesionthereto of an elastomeric material while the said alternate threadswhich contract the greater amount comprise tension-resistant elements inthe fabric.

3. The method according to claim 2 in which the threads having thelesser crimp are made from continuous filament yarn and the threadshaving the greater crimp are made from staple yarn.

.4. The method according to claim 2 in which the threads having thelesser crimp are made from continuous filament nylon yarn.

5. The method according to claim 2 in which the threads having thegreater crimp are made from staple cotton.

6. The method according to claim 2 in which the said thread contractingcondition comprises release of said tension.

7. The method of making a fabric reinforced elastomeric materialcomprising interweaving threads extending generally lengthwise andcrosswise, respectively, of the completed fabric with alternate ones ofthe threads extending in the lengthwise direction formed of continuousfilaments consisting of a single textile substance which elongates whensubjected to tension and with the others of said alternate threadsformed of staple fibers and with all of the threads in the lengthwisedirection subjected to equal tension during weaving, removing thetension after weaving thereby causing said continuous filament threadsto contract a greater amount than said staple fiber threads so that thelatter form spaced projections on either face of the fabric, andapplying elastomeric material to the fabric with the said materialpenetrating between the spaces provided by the said projections therebysecuring the elastomeric material to the fabric while the saidcontinuous filament threads constitute tension-resisting elements in thematerial.

References Cited in the file of this patent UNITED STATES PATENTS1,875,517 Steere Sept. 6, 1932 2,067,816 Barnick Jan. 12, 1937 2,391,950Croft et a1. Jan. 1, 1946 2,401,829 Kahil a- June 11, 1946 2,450,948Foster Oct. 12, 1948 2,515,778 Knowland July 18, 1950 2,574,029 FosterNov. 6, 1951 2,627,644 Foster Feb. 10, 1953 2,701,406 Bloch Feb. 8, 19552,703,774 Morrison Mar. 8, 1955 2,713,193 Robbins et a1. July 19, 19552,720,226 Helwith Oct. 11, 1955 2,793,151 Arnett May 21, 1957

1. THE METHOD OF MAKING A FABRIC REINFORCED ELASTOMERIC MATERIAL ADAPTEDFOR USE IN ARTICLES SUBJECT TO TENSION COMPRISING PROVIDING A FABRICINCLUDING INTERWOVEN THREADS EXTENDING GENERALLY IN DIRECTIONSLENGTHWISE AND CROSSWISE OF THE FABRIC, RESPECTIVELY, WITH ALTERNATETHREADS IN THE LENGTHWISE DIRECTION OF THE FABRIC CONTRACTIBLE BYDIFFERENT AMOUNTS AND WITH ANY SINGLE THREAD OF SAID ALTERNATE THREADSFORMED OF A SINGLE TEXTILE SUBSTANCE, SUBJECTING ALL OF THE THREADS INTHE LENGTHWISE DIRECTION TO UNIFORM TENSION DURING WEAVING, SUBJECTINGTHE FABRIC TO A THREAD:CONTRACTING CONDITION AFTER WEAVING WHEREBY THOSEOF SAID ALTERNATE THREADS WHICH CONTRACT THE LESSER AMOUNT ACQUIREGREATER CRIMP THAN THOSE OF GREATER CONTRACTIBILITY THEREBY FORMINGSPACED PROJECTIONS ON EITHER FACE OF THE FABRIC WHILE THE SAID ALTERNATETHREADS WHICH CONTRACT THE GREATER AMOUNT COMPRISES TENSIONRESISTANTELEMENTS IN THE FABRIC, AND APPLYING ELASTOMERIC MATERIAL TO THE FARICWITH THE SAID MATERIAL PENETRATING BETWEEN THE SPACES PROVIDED BY THESAID PROJECTIONS.